In recent days, as an image sensor has a greater number of pixels, the number of pixels of a captured image obtained by an imaging apparatus increases, and a pixel size tends to be small. While details of a subject can be represented as a result of an increase in the number of pixels, noise increases when the pixel size is small and image quality deterioration becomes distinct. This image quality deterioration can be more effectively corrected by noise cancellation by a spatial filter. However, when the number of pixels of an image increases, the number of pixels to be processed by a spatial filter also increases, and therefore a hardware scale and cost for realizing the spatial filter increase.
From this point of view, it may be appropriate to reduce the number of pixels of an original image to generate a reduced image and perform image processing on the reduced image (see, for example, Patent Literature 1). Consequently, it is possible to prevent a hardware scale from increasing, and a processing time from being longer.